The Wright Brothers

1. The Wright Brothers

2. Chapter Overview • The Wright Brothers • Developing Aircraft Chapter 2, Lesson 1

3. How the Wright Brothers Succeeded in the First Flight • All pilots face three challenges: • Get up in the air • Stay up • Control the craft • Pilots experimented in flight with: • Manned and powered, full-size aircraft • Models • Full-size gliders Chapter 2, Lesson 1

4. How the Wright Brothers Succeeded in the First Flight • The Wrights chose a glider as their starting point • They could focus first on balancing and controlling the aircraft • Power (an engine) could come later • They applied what they learned at each step to make the next one go more smoothly Chapter 2, Lesson 1

5. Step One: Unmanned Box Kite • The Wrights’ kite had • A five-foot wingspan and biplane structure • Struts that connected the upper and lower wings • Bracing strung diagonally between the struts Chapter 2, Lesson 1 Courtesy of the Air Force Historical Research Agency

6. Step One: Unmanned Box Kite • They discovered that they didn’t need to tilt an entire wing to turn the craft: • Needed to twist only the ends of the wings • They called this process “wing warping” • In the summer of 1899, Wilbur Wright successfully tested the kite in a field Chapter 2, Lesson 1

7. Step Two: Manned Gilders • Between 1900 and 1902, the brothers built three gliders • Before putting a man aboard, they flew each glider like a kite • They wanted to test it for control and lift • Only after doing this would they put a man aboard Chapter 2, Lesson 1

8. Wright Gliders • The early glider experiments taught the brothers three important things: • How to control climb and descent • The best design for the shape of the wing • How large the wing area had to be to sustain lift Chapter 2, Lesson 1 Courtesy of Wright State University

9. The First Glider (1900) • In their experiments in 1900, the Wrights placed an elevator at the front of the glider • Earlier designers mounted elevators behind the wings • But the Wrights found it easier to control climb and descent when the elevator was placed forward Chapter 2, Lesson 1

10. The First Glider • They also focused on airfoil—a wing’s profile • Zeroed in on curve of the wing • Tried to design a wing that shifted the center of pressure toward the front edge of the wing • Placed the highest point of the wing’s arc closer to the outer edge than to the center—to create greater stability and control Chapter 2, Lesson 1

11. The First Glider • The brothers test-flew their glider at Kill Devil Hills in 1900 • It didn’t crash, but clearly improvements were necessary • The Wrights headed back to Ohio to build the next version Chapter 2, Lesson 1

12. The Second Glider (1901) • The first glider didn’t have nearly enough lift • So for their 1901 glider, the brothers increased the wing area to 290 square feet • This glider was also a big disappointment • The brothers couldn’t control it well when they tested it at Kill Devil Hills • It flew less than 300 feet—time to return to Dayton! Chapter 2, Lesson 1

13. The Wind Tunnel • The brothers built a wind tunnel in their bicycle shop to test model-size wings • Made them of sheet steel • Cut more than 200 model wings of different shapes Chapter 2, Lesson 1 Courtesy of Wright State University

14. The Third Glider (1902) • This glider had two fixed, vertical rudders behind the wings • Test flights showed that this resulted in erratic behavior during turns • So the Wrights tried a single, movable, vertical rudder • This improved control Chapter 2, Lesson 1

15. The Third Glider • The third glider had: • Forward elevator • Elliptical shape • Longer, skinnier wings • Wing area of 305 feet • Low angle of attack • This design was a success • The brothers took to the air in the North Carolina dunes more than 700 times in the fall of 1902 Chapter 2, Lesson 1 Courtesy of NASA

16. The 1903 Engine viewed from the side Step Three: A Manned, Powered Aircraft • The brothers set out to fit their plane with an engine • They tried to buy one ready made • But no one met their needs or price • So they had their bicycle mechanic, Charles E. Taylor, build them a four-cylinder, 12-horsepower engine Chapter 2, Lesson 1 Courtesy of the Library of Congress

17. Delays • In September 1903 they returned to Kitty Hawk and Kill Devil Hills • First they had to build a trolley track to give their powered aircraft a running start • Bad weather also caused delays • The brothers tossed a coin, and Wilbur won • However, on the first test flight of the Wright Flyer, he crashed it • It took three days to repair the damaged craft Chapter 2, Lesson 1

18. First Flight! • On 17 December, Orville took the controls • The Flyer rose into the air and stayed aloft for 12 seconds and traveled 120 feet • Orville had made the first controlled, sustained, heavier-than-air human flight with a powered aircraft • The brothers took turns piloting the Flyer for three more flights • The fourth and final launch lasted 59 seconds, and the craft traveled 852 feet Chapter 2, Lesson 1

19. Anatomy of the Wright Flyer • Equipped with an engine and propellers • Biplane with wingspan of 40 feet, four inches, and a wing area of 510 square feet • Wings had spars and ribs (covered in muslin) • Struts and bracing between top and bottom wings • Plane also had a front elevator • Rudder at the rear (covered in muslin) • Skids rather than wheels Chapter 2, Lesson 1

20. Anatomy of the Wright Flyer Chapter 2, Lesson 1 Courtesy of Wright State University

21. How the Flyer Worked • The brothers controlled their craft with: • the forward elevator • the use of wing warping • and a single, movable rear rudder • Surprisingly, the pilot did not sit upright • The pilot lay on his stomach in a padded cradle on the lower wing Chapter 2, Lesson 1 Courtesy of Comstock Images

22. How the Flyer Worked • To the pilot’s left was a lever that he used to control the up-and-down movement of the elevator • By moving his hips, he pulled on the cables connected to the wings and rudder (directing the plane left or right) • With the new, flexible rudder, the plane finally turned in the intended direction • The cables attached to the wings twisted one wing down while forcing the other wing up Chapter 2, Lesson 1

23. Orville and Wilbur assembling the 1903 Flyer (detail) Principles of Airplane Flight • To get the Wright Flyer off the ground, the brothers had to solve the principles of flight: • Lift • Drag • Thrust • Angle of attack • Center of pressure • Airfoil • Relative wind Chapter 2, Lesson 1 Courtesy of “Wright State University

24. Principles of Airplane Flight • An engine and propellers gave Wilbur and Orville the ability to use not only lift but also thrust to propel their plane • Vertically mounted propellers could provide the airflow for thrust • They needed 90 pounds of thrust to propel the Wright Flyer • Their 12-horsepower engine and the large propellers proved equal to the task Chapter 2, Lesson 1

25. Wright Brothers’ Involvement With the US Army • The Wright brothers continued refining their airplane • In January 1905, they had contacted their representative in Congress (R. M. Nevin) and tried to interest the US government in buying their airplane • Their offer was turned down Chapter 2, Lesson 1

26. Wright Brothers’ Involvement With the US Army • The British and French governments were interested in buying the Flyer • But the brothers wanted the US government to have the first crack at owning a Wright Flyer • On 22 May 1906 they received a government patent for their invention Chapter 2, Lesson 1

27. The Wright Brothers’ Patent Chapter 2, Lesson 1 Courtesy of the U.S. Air Force

28. Bids for a Government Plane • On 23 December 1907, Gen James Allen sent out a request for bids to build a plane for the government • The Wright Flyer met the bid requirements • Orville Wright signed a contract on 10 February 1908 selling the Flyer to the US government Chapter 2, Lesson 1

29. Ways the Wright Brothers Contributed to Army Aviation • Orville spent much of 1908 and 1909 improving the Flyer • He made more test flights and took up military passengers • One such flight tragically ended in a crash that seriously injured Orville and killed 1st Lt Thomas Selfridge—the first US military aviation casualty Chapter 2, Lesson 1

30. Ways the Wright BrothersContributed to Army Aviation • The brothers switched roles in mid-1909 • Wilbur trained two pilots for the Army—1st Lt Frank P. Lahm and 2d Lt Fredric E. Humphreys • A third pilot, 1st Lt Benjamin Foulois, got instruction late that month • Foulois went on to achieve the rank of major general and was also chief of the Army Air Corps Chapter 2, Lesson 1

31. Army Airplanes • It took a while for the Army to decide how to use airplanes during war • At first, the Army thought that airplanes would be useful only for aerial reconnaissance • World War I brought about a change in strategy • But before that could happen, airplanes needed improvements to make them faster, sturdier, and more reliable Chapter 2, Lesson 1

32. Next…. • Done—the Wright brothers • Next—developing aircraft Chapter 2, Lesson 1 Courtesy of NASA